Embodiments of the present disclosure relate to downhole equipment circuitry, downhole equipment, and methods of assembling downhole equipment circuitry.
There are numerous environments in which harsh conditions pose difficulties for the designers of electronic systems. These include environments in which there are, for example, high temperatures, high pressures, large shocks, and large amounts of vibration.
Typically, a modern electronic system may comprise a plurality of interconnected circuits. These circuits may include, for example, multi-chip modules (MCMs) in which a plurality of different integrated circuits are provided on a single substrate and/or may include ceramic circuits in which a circuit (such as a printed circuit) is provided on a ceramic substrate (these are particularly useful in harsh environments).
The arrangements of the plurality of interconnected circuits within a device may be driven be a number of different factors, including the available space, and the need to minimise relatively delicate connections between the circuits.
An example of where such arrangement can be found is in downhole equipment used down a borehole (e.g. a borehole for hydrocarbon exploration or extraction). The downhole equipment may be exposed to relatively harsh conditions within the borehole—including high temperatures, high pressures, exposure to large amounts of vibration, and exposure to significant mechanical shock. Downhole equipment also has, by the nature of the borehole, relatively restrictive space/volume requirements.
In some conventional downhole equipment, such circuits have been placed such that they extend along a length of the downhole equipment (i.e. a primary plane the or each circuit is generally parallel to a longitudinal axis of the downhole equipment). This allows the circuits to extend along what has conventionally been the longest length of the downhole equipment. This minimises the number of interconnections between the circuits and places the majority of those interconnections along the same plane. However, recently, there has been a drive to reduce the size (i.e. length) of the downhole equipment. This has reduced the space available for the circuits.
The circuits have also conventionally been linked together by wire harnesses and/or the circuits have been mounted on extensive printed circuit boards (which may then also be linked by wire harnesses). Typically, one or more circuit is mounted to a chassis member of the downhole equipment and such circuits are conventionally linked by a wire harness. Other circuits are mounted on printed circuit boards which are then directly or indirectly mounted to the chassis member.
Wire harnesses and the use of extensive printed circuit boards in the conventional equipment uses yet more valuable space in the equipment and makes the equipment relatively heavy. The wire harnesses are also prone to problems in their reliability and the reliability of their construction. The connection points of the wire harnesses are relative weak points which are prone to failure during the operation life of the equipment. Of course, wire harnesses are also slow to construct and, furthermore, take a relatively long time to install and can be awkward to install in some instances. The use of extensive printed circuit boards limits the amount of space reduction which is possible and can also be prone to failure in harsh environments.
There is a need, therefore, to provide alternative methods of interconnecting circuits, e.g. within downhole equipment.